Computed tomography (CT) is a technology that makes use of computer-processed combinations of X-ray images taken from different angles to produce cross-sectional images. The CT technology has been widely used in medical diagnosis. During a process of a CT scanning, artifacts including metal artifacts or streak artifacts may occur. The artifacts may reduce the image quality and influence the diagnosis results. There is a need for a system and method to remove the artifacts from the images and improve the image quality.